1. Field of the Invention
The present invention relates to a method and apparatus for mounting electronic components on a substrate.
2. Background
There are various kinds of electronic products, such as a digital camera, a cellular phone, a personal digital assistant (PDA), an MP3 player, and a personal multimedia player, on the market. Such electronic products are becoming more miniaturized for portability. Accordingly, more electronic components, such as semiconductor devices, should be mounted within a smaller area in the electronic products.
A conventional method of mounting electronic components includes printing a solder paste onto a substrate, mounting the electronic components on the solder paste, and reflow-soldering the electronic components.
Among the electronic components mounted on the substrate, there may be some exceptional electronic components having reliability under low temperature limits. Although conventional electronic components can withstand a temperature of about 260° C., some exceptional electronic components can withstand a temperature of just about 200° C. In order to mount the exceptional electronic components with the other electronic components on the same substrate, according to the conventional method, the exceptional electronic components have to be manually soldered on the substrate.
Another conventional method of mounting electronic components includes printing a first solder paste, mounting first electronic components, forming a mask covering the first mounted electronic components, printing a second solder paste by using the mask, and mounting second electronic components. However, if the first electronic components are thick, it is difficult to form the mask covering the thick first electronic components, and it is also very difficult to move a squeezer when applying the second solder paste.
Another conventional method includes mounting electronic components having reliability under different temperature limits on different substrates. However, this approach goes against the trend toward minimizing electronic products.